This time she’s “The Duchess,” a coltish free spirit wedded in 1774 to a cruel duke (Ralph Fiennes) who moves as stiffly as a man who has just sat on a candlestick and imposes a one-kiss limit on his foreplay.

He wants an heir; she kicks out daughters. He takes a mistress; she takes a mister. Everything is predictable three scenes in advance, and it’s all stale, stuck, stolid. The movie was produced by an organization known as the “BBC.” Bland Brit Crapola? Earl Grey turns out to be an important character, but the movie is cine-Sanka.

Knightley is a paper doll around whom the movie wraps hoop skirts and 21st century victimology. Scene after feeble scene coughs up the same point about how tragically ahead of her time she is: She’s headstrong, she’s political, she argues for women’s rights and she gambles. When the Duke (that’s dyook to you, bub) asks her why women’s dress is so complicated she replies that it’s “our way of expressing ourselves.” Tell it, Sis!

The only conceivable reason to make a movie about the girl in the Bride of Frankenstein wiggery is that the duchess was a Spencer, distantly related to Princess Di.

And the intended viewers are Di-dazzled celebazine readers (“18th Century Aristos: They’re Just Like US!”) who fancy themselves a bit posh as they get French tips put on their nails and see nothing laughable about lines like, “Intercourse is not just about offspring. In fact, it can be rather pleasurable,” and “Change is upon us! We shall not go back to the old ways!” – which is thrown in for no reason and never referred to again. Then there’s this exchange: “All London is talking!” “Let them talk!”

The assumed intelligence level of the audience is even revealed in a title: “The City of Bath.” Not the tub of Bath?

Fops and noblewomen keep wafting in to tell us how famous and beloved the Duchess is, though the only things that are interesting about her are that she’s Keira and she’s got these wigs. She looks at her newspaper clippings in a scene that works the same way as the obligatory Larry King cameo in a contemporary movie. Truly famous people don’t need to wave their press kits under your nose.

Every “sumptuous” set is as dull as the “smoldering” glances the Duchess throws at her lover over the gaming table, or the “shocked” hurt on the Duchess’ face when she finds out her husband has a lover. There is no repartee; neither are there devilish “Dangerous Liaisons” twists or even a “Marie Antoinette” sense of lovely strangeness. Instead, everyone natters on about “love” like guests on daytime TV. Sorry, love wasn’t the issue, not among the power-mad twit class of that scepter’d isle.

Fiennes is wasted. He can’t find a use for his subtlety since he is only given one note to growl. His role calls for an actor who realizes the limitations of the piece and has no reservations about spewing villainy all over the place. Ian McShane? Basil Rathbone?

Did I mention that it’s all a true story? Well, sort of. The credits end with a 60-word disclaimer about the movie’s non-strict policy regarding truth; 56 words could have been saved if the title had just said, “We made up stuff.”